The present invention relates generally to fuel injectors and the wear of fuel injectors over time and more particularly to a fuel injector wear compensation methodology that alters the injection schedule within an engine cycle over time.
As with many internal combustion engine components, fuel injectors are known to wear with use over time. This wear impacts the fuel injector's injection characteristics. In turn, effects on the engine using the worn fuel injector(s) result. With high pressure fuel injectors, in particular, fuel can cavitate in the nozzle of the fuel injector causing uneven wear over time. This uneven wear can cause further cavitation in the nozzle. Cavitating fuel, ultimately, can act as a restriction on fuel flow, reducing the effective discharge coefficiency of the fuel nozzle, thereby resulting in reduced fuel flow through the fuel injector nozzle for a given commanded injection duration and pressure. This fuel injector performance degradation, in turn, ultimately affects engine performance and efficiency. With fuel injector wear there is also a concomitant increase in particulate matter (PM) in the exhaust emissions.
Accordingly, there is an ongoing need for both improving upon an understanding of these fuel injector wear characteristics and then also accounting for this improved understanding in the operation of engines and their fuel injector systems.